1. Field of the Invention
The invention relates to a drive device for a motor-driven tilt element that can be moved between an open position and a closed position, having an electric-motor driven spur gear drive. A tilt element can be understood to mean an outwardly opening closure part that is pivotable, which is to say hinged on one side, for example a vent window, a pop-up roof, or the like, in a motor vehicle.
2. Description of the Background Art
A drive mechanism is known from DE 197 57 346 C2, which corresponds to U.S. Pat. No. 6,056,348, and in which the driving force of an electric motor can be transmitted to a pivoting window via a worm-and-spur drive to a first link that is integral with an output shaft and a second link that is coupled with the first link. During an opening and closing motion of the window, the connection point between the two links moves along a curved path of approximately 180°, while the connection point between the second link and the window pane moves back and forth along a straight path. The curved path of the connection point extends on the side of the drive shaft opposite a pivot hinge for articulating the window pane that represents the circle center of a path forming a semicircle. The second link between the connection point and the window pane is curved in design in one embodiment, and thus surrounds the output shaft even when the vent window is closed.
In a power window actuator known from DE 42 18 507 C2, with an electric motor drive and multi-stage geared spindle drive, and with a similar pivoted lever mechanism with two levers connected together in an articulated manner whose articulation point for opening and closing the outwardly opening side window again is pivoted along an arcuate path about an axis of shaft rotation, the articulation point is located on the side opposite the window pane below the axis of rotation when the window is in the closed position. In this way, the window is secured against unwanted (manual) opening.
If such drive devices are also to be operable in so-called automatic travel, then they are subject in principle to the same legal requirements as window regulators for windows that can be raised and lowered, for which a maximum pinching force of typically 100N is permissible for a so-called 4 mm rod (upper pinch gap limit) in automatic travel in the direction of closure.